Hand of Benediction

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1- Introduction

2- Anatomical Overview

3- Causes of Median Nerve Injury

4- Treatment

Introduction

The “Hand of Benediction” is a clinical sign resulting from median nerve injury, often associated with the inability to flex the first three fingers when attempting to make a fist. This condition highlights the crucial role of the median nerve in hand function.

Appearance: When the patient attempts to make a fist, the index and middle fingers remain extended, while the ring and little fingers flex normally.
Mechanism: This occurs because the flexor muscles for the index and middle fingers (FDS and FDP) and the thenar muscles are impaired, while the ulnar nerve-innervated muscles that flex the ring and little fingers remain functional.

Anatomical Overview

Anatomy Involved

Median Nerve:
- Origin: Arises from the brachial plexus, with contributions from the lateral and medial cords (C5-T1).
- Course: Travels down the arm, through the cubital fossa at the elbow, and into the forearm. It passes through the carpal tunnel into the hand.
- Innervation: Supplies motor innervation to several muscles of the forearm and hand, and sensory innervation to parts of the palm and fingers.
Muscles Affected:
- Forearm Flexors:
  - Flexor Digitorum Superficialis (FDS): Flexes the middle phalanges of the index and middle fingers.
  - Flexor Digitorum Profundus (FDP) (lateral half): Flexes the distal phalanges of the index and middle fingers.
  - Flexor Pollicis Longus (FPL): Flexes the thumb.
- Thenar Muscles:
  - Abductor Pollicis Brevis: Abducts the thumb.
  - Flexor Pollicis Brevis: Flexes the thumb.
  - Opponent’s Pollicis: Opposes the thumb.
- Lumbricals (1st and 2nd): Flex the metacarpophalangeal joints and extend the interphalangeal joints of the index and middle fingers.

Causes of Median Nerve Injury

Trauma: Direct injury to the nerve from fractures, lacerations, or penetrating injuries.
Compression: Carpal tunnel syndrome, where the median nerve is compressed at the wrist.
Systemic Conditions: Diabetes, which can cause peripheral neuropathy affecting the median nerve.
Tumors or Masses: Space-occupying lesions pressing on the median nerve.

Treatment

Conservative Management:
- Splinting: To support the hand and maintain proper positioning.
- Physical Therapy: To maintain muscle strength and joint flexibility.
- Medications: NSAIDs for pain and inflammation; corticosteroids in some cases of compression.
Surgical Intervention:
- Decompression Surgery: For cases of carpal tunnel syndrome.
- Nerve Repair or Grafting: In cases of traumatic injury.
- Removal of Tumors or Masses: If a mass is compressing the nerve.